触发管型气体开关的导通机制

Discussion of Breakdown Mechanism in Gas-insulated Trigatron Switches

为优化触发型3电极开关的性能,评估其击穿时延,分析了这种开关的导通机制。触发管型开关存在快导通(FBM)与慢导通(SBM)等2种导通机制。基于气体放电理论推导了触发管型气体开关的击穿时延模型,并分析了不同导通机制下的击穿过程。基于Raether击穿判据,计算了开关进入快导通机制的工作欠压比下限。实验得到,快、慢导通机制之间的欠压比阈值为0.7。开关内的等效电场可分解为静态畸变电场与动态畸变电场,结合时延模型能合理反映导通时延受工作条件与触发能量影响的动态过程。在快导通机制下,欠压比与静态电场增强系数起着主要影响;在慢导通机制下,除欠压比之外,触发脉冲能量的影响同样重要,此外还需考虑消游离对导通的影响。得到的结果可供提高触发管型气体开关的导通性能的设计与研究借鉴。

To optimize gas-insulated trigatron switches and evaluate their break time, we analyzed their breakdown me- chanism, and found two modes of the breakdown, namely, the fast-breakdown mode （FBM） and the slow-breakdown mode （SBM）. Based on the gas discharge theory, a model of breakdown delay was proposed, which was used to further explain the breakdown process of the two breakdown modes. Using the Raether breakdown criterion, we calculated the bottom value of undervoltage ratio for transiting into FBM from SBM, which was 0.7 according to experiments. It is found that the electric field （EF） in a trigatron switch is composed of a static EF and a dynamic EE Thus, the breakdown delay model can reasonably reflect the dynamic process of the breakdown time affected by working conditions and trigger energy. The static EF enhancement coefficient and the undervoltage ratio play an important role in FBM, while the trigger energy and the undervoltage ratio play an important role in SBM. The deionization of gas should also be considered in SBM. The obtained results could be referred by design and researches on improving trigatron switches.